Among world leaders who engage in twiplomacy — the use of Twitter for diplomatic relations — President Obama wins superlatives for the most followers but Pope Francis is the most influential, said Burson-Marsteller, a global public relations and communications firm. Pope Francis, who started to tweet under the handle @pontifex on March 17 — a few days after he was elected pope, has rapidly become a Twitter star even though he has only sent out about 100 tweets. The study deemed him most influential based on the number of times people share his tweets — an average of 11,000 retweets per message on his Spanish-language account. In contrast, Obama averages 2,309 retweets for every tweet he sends.